Wings are airfoils that create lift when they move through the air. Wings can have many different designs, shapes and configurations. To achieve desired weight and performance, most large aircraft wings are constructed as hollow structures made of aluminum and possibly other materials. See FIG. 1A. The skin, typically thin aluminum sheets attached to the wing structure by rivets or other fasteners, provides the surface that is in contact with the air. Within the wing structure, ribs running from the wing's leading edge to its trailing edge (i.e., across the wing) support the skin and transfer the force from the skin to structural members within the wing structure such as longitudinal spars and stringers that run the span of the wing. See Federal Aviation Administration, Aviation Maintenance Technical Handbook, Vol. 1 (“Airframe”), Chapters 1 and 4, FAA-H-8083-31 (2012) https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/amt_airframe_handbook/, incorporated herein by reference as if expressly set forth.
In a more specific example, FIG. 1 shows a cross-sectional view of an example non-limiting wing design including a shear joint type semi-wing junction. The FIG. 1 view shows the semi wing structure as if cut from top to bottom looking for example from the wing's leading edge to the wing's trailing edge, with the upper skin 52 defining the top wing surface, and the lower skin 54 defining the lower wing surface. Gaps between Right and Left Upper skins are shown by 61 and gaps between Right and Left Lower skin are indicated by 61′. Upper skin 52 and lower skin 54 are held and supported by structure including or consisting of shims, a rib and splices. In particular, a rib 0 (56) connects an upper T profile member 58 which attaches to the upper wing structure. Similarly, a lower T profile member 60 attaches the rib 0 (56) to the lower wing structure. Rib 0 (56) is the aircraft “Y” position reference. The T profile elements 58, 60 are in turn bonded to splice elements 62, 64. Namely, the upper T profile 58 is bonded to an upper splice 62, and the lower T profile 60 is bonded to a lower splice 64. The rib 0 (56) thus holds the upper wing structure to the lower wing structure, with splice elements 62, 64 retaining the skin 52, 54 to T profile elements 58, 60. The splice elements 62, 64 splice together different parts of the semi-wing to form a unified integrated structure.
To avoid bending and shear stress, it is desirable to have virtually no gap between upper splices 62, 64 and skin 52, 54. For example, FIG. 2 shows a simulation with gaps 76, 78 between the junction parts. In particular, there is a gap 76 between the upper splice 62 and the skin 52, and a gap 78 exists between the lower shear element 64 and adjacent structures.
Shims 66, 68, 70, 72 have conventionally been used in the past to fill such gaps between the junction parts. Thus, a shim 66 is typically disposed between upper splice 62 and skin 52; a shim 72 is typically disposed between lower splice 64 and skin 54; a shim 68 is typically disposed between skin 52 and T profile element 58; and a shim 70 is typically disposed between skin 54 and T profile element 60. See FIG. 1.
During semi-wing junction assembly, both semi-wings are aligned with a best algorithm that minimizes deviations in aerodynamic and structural specifications. As semi-wings are not identical to each other, gaps between both parts are generated and shims 66, 68, 70, 72 are manufactured and inserted to avoid bending and shear stress. It would be desirable to avoid the need for shims.
A known process for assembling parts without the need to insert shims during the process starts with gap measurement between a first part and a theoretical model. A new model of the gap insertion is created (manufactured) and placed on the tooling of the part to be joined. Once the second part has the shape of the gap and it is aligned to first part, the gap between parts is eliminated. However, such a process can have disadvantages such as:
For each shipset junction, a new insertion on the tooling must be manufactured to minimize the gap; and
The production cycle (time it takes to manufacture the assembly) increases because the junction depends on measurement of the first part before manufacturing the second part.